# if 5>12:
#     print("5 is greater than 12")
#     print("222222")
# else:
#     print("5 is not greater than 12")


# age=30
# if age<18:
#     print("18 is underaged")
# elif age>=18 and age<30:
#     print("you are young")
# elif age>=30 and age<50:
#     print("you are middle-aged")
# else:
#     print("you are old")
#     #判断是否是闰年
# year= int (input("请输入年份"))
# if(year%4==0 and year%100!=0 or year%400==0):
#     print("%d是闰年" %year)
# else:
#     print("%d不是闰年" %year)
#     #a b c比较大小
# a=int(input("请输入a"))
# b=int(input("请输入b"))
# c=int(input("请输入c"))
# if a>b:
#     if a>c:
#         print("a is the greatest number")
#     else:
#         print("c is the greatest number")
# else:
#     if b>c:
#         print("b is the greatest number")
#     else:
#         print("c is the greatest number")
#计算机实现加减乘除
num1=float(input("请输入第一个数字"))
num2=float(input("请输入第二个数字"))
op=input("请输入运算符")
if op=="+":
    print(num1 + num2)
elif op=="-":
    print(num1-num2)
elif op=="*":
    print(num1*num2)
elif op=="/":
    print(num1/num2)
else:
    print("输入错误")